Mercedes-Benz power ruled the roost in the opening practice session of the Canadian Grand Prix, with Jenson Button emerging at the top of the timesheets, just edging out Michael Schumacher in the works Mercedes GP car.

Lewis Hamilton finished third-quickest in the sister McLaren, with Nico Rosberg just behind in fourth place.

The defending World Champion set a best time of 1:18.127 as Montreal’s return to the F1 calendar made its highly anticipated start, with less than a quarter of a second covering the top four.

With the exception of a few drops of rain, the 90-minute session ran in dry conditions, and it took a while for the drivers to find their comfort zone in the opening half-hour, with many pilots reporting tricky, slippery conditions on the recently-resurfaced circuit. It was only after 30 minutes that drivers started to post competitive lap times, and it was well into the session before the big boys started to knock down the fastest times.

Once this happened, the session looked like being a battle between the ‘F-duct’ equipped McLarens and Mercedes GP cars, with Button and Schumacher looking the most promising. McLaren would hold a 1-2 on the timesheets for a period, but eventually the seven-time World Champion was able to split the pair. Schumacher was certainly not taking it easy, with a few near-miss moments with the concrete walls and the occasional missed apex under braking.

Indeed plenty of drivers were set on exploring the limits of the Circuit de Gilles Villeneuve, with no less than five drivers – including the likes of Fernando Alonso, Vitaly Petrov, Sébastien Buemi, Bruno Senna and Hamilton himself – enjoying trips over the chicane run-offs. Pedro de la Rosa (pictured) also blotted his copybook with a spin in his Sauber at the hairpin.

Of the other drivers on-track, Sebastian Vettel was the best-placed of the Red Bulls in fifth, and team-mate Mark Webber was mired in a lowly 14th. Robert Kubica followed Vettel on the timesheets with sixth overall in his Renault.

The two Williams cars enjoyed a surprise top-ten result in the opening session, and certainly haven’t featured this far north on the timesheets for a little while. Whether or not this form can be sustained throughout the weekend remains to be seen…

At the back of the pack, both Hispania Racing cars outpaced the Virgin VR-01s, no doubt to the displeasure of the Manor Racing squad. Poor Lucas di Grassi failed to post a time after being confined to the garage for much of the session, and then later grinding to a halt at Turn 6 not long after joining the track.